1. Field of the Invention
The present invention relates to a medical image processing device that enables displaying a medical image that is a captured image of an object of interest in a body cavity and a method for operating a medical image processing device.
2. Description Related to the Prior Art
In diagnosing stomach cancer, it has been recognized that the onset of the stomach cancer is closely related to the presence of Helicobacter pylori (H. pylori). In 1994, WHO (the World Health Organization) announced that the H. pylori is a carcinogen. The eradiation of the H. Pylori infection has been performed to reduce the stomach cancer. After the eradication, whether the eradication has been successful is examined.
Whether a patient is infected or uninfected (not yet infected) with the H. pylori is examined by a blood test or by using an endoscope system, which comprises a light source device, an endoscope, and a processor device. In the endoscope system, an image of an object of interest (hereinafter simply referred to as the object) is displayed on a monitor based on RGB image signals generated by capturing an image of the object with an image sensor while the object is irradiated with illumination light from the endoscope. In a case where diffuse redness appears in the image on the monitor, it is diagnosed that there is a high possibility of the presence of the H. pylori, which is likely to cause cancer.
It is also known that the presence of the H. pylori correlates with IHb (also referred to as the hemoglobin index, which is represented by a G/R ratio between a G image signal and an R image signal) (see Japanese Patent Unexamined Application Publication No. 2003-220019). In this document, the IHb is used as an index for determining whether the eradication of the H. pylori infection has been successful. According to this document, in the case where the IHb is greater than a threshold value “59”, it is diagnosed that the eradiation of the H. pylori infection has not been successful and the H. pylori is still present. In the case where the IHb is less than the threshold value “59”, it is diagnosed that the H. pylori has been eradicated successfully.
In a feature space formed by the B/G ratio (the vertical axis, the ratio between the B image signal and the G image signal) and the G/R ratio (horizontal axis) shown in FIG. 30, the coordinates corresponding to a portion (of the object) uninfected with the H. pylori are distributed in an area “A”. The coordinates corresponding to a portion (of the object) infected with the H. pylori are distributed in an area “B”. The coordinates corresponding to a portion (of the object) in which the eradication of the H. pylori infection has been successful are distributed in an area “C”. The areas “A”, “B”, and “C” may coexist in the feature space. There are cases where the distinction among the areas “A”, “B”, and “C” is difficult based only on the value of the G/R ratio (the horizontal axis) representing the IHb. It has been requested to display an image that enables the distinction between the infection of the H. pylori and the successful eradiation of the H. pylori, without using the IHb.